Modules are quickly switching to using nan, which is required anyway for working with both 0.10 and 0.12, so io.js merely accelerated the incentive to use it.

Modules are quickly switching to using nan, which is required anyway for working with both 0.10 and 0.12, so io.js merely accelerated the incentive to use it. As far as "big sites", several are starting to roll out io.js deployments. Most places don't blog about every upgrade to every internal piece of infrastructure. If you're doing the SOA thing properly, you can start rolling out io.js for new services without removing the versions of node used for other stuff. At npm, we have some io.js, lots of node 0.10, erlang, java, spidermonkey, python, redis, postgres, etc. It's pretty common to use different stuff side by side in little servers that talk to one another. Less dramatic to talk about than pretending your'e gonna make some big switch-over though.